The Subframe CA5551 is a lightweight 6" waterproof composite-toe work boot with an entirely non-metallic build — composite toe, non-metallic shank, and non-metallic hardware, with no steel anywhere in it.
Key Features of the Carolina CA5551
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Composite Safety Toe — Non-metallic toe meeting ASTM F2413 I/C for impact and compression, with reduced cold transfer.
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Waterproof SCUBALINER™ — Carolina's sealed proprietary waterproof lining system.
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Utopia Dark Coffee Leather Upper — Durable leather in a lightweight build.
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Mesh Lining & Removable Dual-Density EVA Footbed — Breathable, with a memory-foam-topped insert and improved heel cup.
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EVA Midsole — Lightweight cushioning.
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Non-Metallic Shank & Non-Metallic Hardware — Composite throughout, down to the eyelets.
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Electrical Hazard Rated — Tested to withstand up to 18,000 volts at 60Hz for one minute without leakage.
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Cement Construction & Oil/Slip-Resisting Rubber Outsole — Light, flexible, and grippy.
Not a Scrap of Steel
Most composite-toe boots still hide a steel shank underfoot and steel eyelets up the vamp. The Subframe doesn't: the toe cap, the shank, and every piece of hardware are non-metallic. That takes weight out of the boot, keeps the toe box from going cold on a winter morning, and leaves nothing to rust when the leather stays wet.
Light Without Giving Up Protection
The composite toe meets the same ASTM F2413 impact and compression thresholds as steel, and the EVA midsole and cement construction keep the whole boot light and flexible underfoot from the first day.
Why Choose the CA5551?
A lightweight, waterproof, fully non-metallic composite-toe boot — protection with nothing heavy or cold between you and the ground.
Similar Styles to Consider
Want a carbon composite toe with a premium footbed? See the Duke CA5540. Browse the full Carolina collection at Overlook Boots.
Frequently Asked Questions
Is the CA5551 static-dissipative (SD)?
No, and this is worth getting right. Carolina builds a separate SD version of the Subframe under a different style number. The CA5551 is Electrical Hazard rated, which is the opposite property: EH insulates you from live circuits, while SD deliberately conducts static charge to ground. The two ratings are mutually exclusive. If your workplace requires SD footwear, this is not the boot.
Does it have a zipper?
No. The CA5551 is a standard lace-up with non-metallic hardware.
Why choose non-metallic hardware?
Metal eyelets and hooks corrode where leather stays damp, and they conduct cold straight through the vamp. Composite hardware does neither, and it takes a little more weight out of a boot that's already built around being light.
How long does the waterproofing last?
The SCUBALINER™ is a sealed membrane rather than a surface coating, so it doesn't wash off. Conditioning the leather and keeping the seams clean is what keeps it working over the life of the boot.
Does the EH rating still apply when the boots are wet?
Treat it as reduced. EH testing is performed under dry conditions; water, damp leather, and worn outsoles all degrade insulation. EH footwear is secondary protection, never a replacement for de-energizing a circuit or primary PPE.
